Oil and gas wells are known having a well bore for passing fluid, transversely across a side of the well bore at a down hole location of the well bore and longitudinally in the well bore, between a geological formation located at the down hole location and a top portion of the well bore. The pressure of the fluid flowing across the side of the well is an important parameter to know by operators at the top of the well. Other parameters of the fluid as it flows across the side of the well may also be important to know at the top of the well. For example, during fracturing, when fluid is passed into the geological formation, pressure at the down hole location is important in determining whether a fracture is vertical or horizontal and to determine growth parameters of the fracture. Fluid pressure and temperature at the down hole location of a producing well, where fluid is flowing from the geological formation to the top of the well, may also be important in some situations. However, remoteness of the down hole location from the top of the well, high flow rates of the fracture fluid across the side of the well and the harsh environment down hole create difficulties in reliably recovering data representing the pressure and other parameters from the fluid at the down hole location..
Therefore, a need exists for easy to use apparatus and methods for recovery, at the top of a well bore, data which accurately and reliably represents a parameter, particularly pressure, of a fluid and particularly a fracture fluid, as that parameter exists in the fluid flowing through the side of the well at the down hole location.